Isolation and Characterization of Antibacterial Metabolites Produced by Streptomyces species from Escravos River, Delta State, Nigeria

Etinosa O. Igbinosa1,2, Areghehefe E. Igelige2, Isoken H. Igbinosa3, Abeni Beshiru2, Emmanuel E. Odjadjare4, Frederick O. Ekhaise2 and Anthony I. Okoh1
1SAMRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Private Bag X1314 Alice 5700, South Africa.
2Department of Microbiology, Faculty of Life Sciences, University of Benin, PMB 1154, Benin City, Nigeria.
3Department of Environmental Management and Toxicology, Faculty of Life Sciences, University of Benin, PMB 1154, Benin City, Nigeria.
4Department of Basic Sciences, Benson Idahosa University, PMB 1100, Benin City, Nigeria.
Corresponding Author: [email protected]

The isolation of Streptomyces sp that yields bioactive molecule is of significant importance in the advancement of new metabolite to combat pathogen. Water, soil and sediment samples were obtained from Escravos River, Delta State. The analysis was carried out using standard culturebased method and polymerase chain reaction approach for identification of the isolates. Of the thirty-six putative Streptomyces sp screened using ethyl acetate crude extracts, five showed varying levels of antimicrobial activities against test bacterial isolates used. This five putative Streptomyces were further identified by partial sequencing the 16S rDNA amplified polymerase chain reaction (PCR) products. The BLAST analysis revealed 99-100% Streptomyces sp similarity in the GenBank nucleotide database. The five Streptomyces sp were ESC003 (Streptomyces griseus), ESC012 (Streptomyces griseus), ESC021 (Streptomyces sp.), ESC022 (Streptomyces fulvissimus) and ESC030 (Streptomyces sp.). Physiological conditions for optimum biomass yields were found to be pH 7 temperature at 28°C incubation days (7-10) and specific rate of metabolite production at day 6 (0.004-0.0045 day-1) from the 5 Streptomyces sp characterized. The MIC values unveiled by all the extracts ranged from 0.016 to 0.056 mg/mL. The minimum bactericidal concentration (MBC) of the extracts ranged between 2.5 and >10 mg/mL. On the time kill assay, the utmost reductions in cell population’s density were revealed by ESC021 and ESC030 against Staphylococcus aureus ATCC 25823. Findings from this study revealed that extracts of the Streptomyces isolates from Escravos River have antimicrobial properties with the potential for novel drugs discoveries.

Keywords: Streptomyces, bioactive compounds , test bacteria , crude extract , antibacterial
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